Skewness of sea level variability of the world's oceans

Abstract

Skewness of sea level variability for the world's oceans is calculated using gridded altimeter data for the period 1993–2001. Many well‐known ocean features can be identified in the skewness map, including the Gulf Stream, Kuroshio Extension, Brazil‐Malvinas Confluence, and the Agulhas Retroflection. It is shown, through an idealized example and results from a quasi‐geostrophic model, that sea level skewness can be used to identify the mean path of unstable ocean jets and also regions dominated by eddies with a preferred sense of rotation. These ideas are confirmed with a more detailed analysis of the skewness fields for the northwest Atlantic and Agulhas Retroflection region. Finally, it is argued that sea level skewness, like variance, is a potentially powerful diagnostic for testing the realism of high‐resolution ocean circulation models.